Ch. 15 Darwin’s Theory Ch. 15 Darwin’s Theory of Evolutionof Evolution

A. VoyageA. Voyage of the of the BeagleBeagle

• December of 1831-December of 1831-

• Beagle set out from EnglandBeagle set out from England

• five-year cruise around the world five-year cruise around the world with Darwin on boardwith Darwin on board

•

B. Darwin’s ObservationsB. Darwin’s Observations

• 1. Living diversity1. Living diversity

• Brazilian rain forest Brazilian rain forest

• Galapagos Islands Galapagos Islands

• Madagascar Madagascar          

• 2. Fossils2. Fossils

• Preserved remains of ancient Preserved remains of ancient organismsorganisms

After being on the boat for 5 years…he went home to England

C. Ideas That Shaped C. Ideas That Shaped Darwin’s Thinking…Darwin’s Thinking…

• 1. An Ancient, Changing Earth1. An Ancient, Changing Earth

• Earth might be many millions of Earth might be many millions of years oldyears old

• Hutton and LyellHutton and Lyell

• If the earth is changing, If the earth is changing,

• the life on earth might be the life on earth might be

• changing, toochanging, too

• 2. Lamark’s Hypotheses2. Lamark’s Hypotheses

• Aquired characteristics are inheritedAquired characteristics are inherited

• Wrong! Wrong!

• Why do we care?Why do we care?

• Paved way for scientists to start Paved way for scientists to start thinking about what might cause thinking about what might cause living things to adapt to their living things to adapt to their environmentenvironment

C. Ideas That Shaped C. Ideas That Shaped Darwin’s Thinking…Darwin’s Thinking…

• 3. Population Growth3. Population Growth

• Thomas malthus Thomas malthus

• babies were being born faster that babies were being born faster that people were dying people were dying

• Same is true for other living things?Same is true for other living things?

• What determines which living things What determines which living things live and which die?live and which die?

C. Ideas That Shaped Darwin’s C. Ideas That Shaped Darwin’s Thinking…Thinking…

D. Darwin’s SolutionD. Darwin’s Solution

• Read 378-379 Read 378-379

• What happened next?? What happened next??

• What motivated Darwin to do this??What motivated Darwin to do this??

• He wrote a book and in 1859 He wrote a book and in 1859 published a book called published a book called On the Origin On the Origin of Speciesof Species

• An essay he received that contained An essay he received that contained the same ideas he had…the same ideas he had…

D. Darwin’s Solution-D. Darwin’s Solution-Evolution by Natural Evolution by Natural

SelectionSelection

1. There’s a 1. There’s a struggle for struggle for existenceexistence

2. Survival of the fittest2. Survival of the fittest

FitnessFitness is the ability to survive and is the ability to survive and reproducereproduce

AdaptationAdaptation is a trait that increases is a trait that increases chances of survivalchances of survival

3. 3. Decent with Decent with modificationmodification

-species today look a little -species today look a little different than their ancestorsdifferent than their ancestors

Read 380-386Read 380-386

• Handout with questionsHandout with questions

• Due today OR tomorrow at beginning Due today OR tomorrow at beginning of periodof period

E. Evidence of EvolutionE. Evidence of Evolution

• 1. Fossil record1. Fossil record

• 2. Geographic distribution of living 2. Geographic distribution of living speciesspecies

• South AmericaSouth America

• AustraliaAustralia

• MadagascarMadagascar

• 200 mya?200 mya?

• Broke up about 130 myaBroke up about 130 mya

• 3. Homologous Structures-develop from similar 3. Homologous Structures-develop from similar structuresstructures

4. Vestigial organs-functionless in some, useful in others4. Vestigial organs-functionless in some, useful in others

• 5. Embryological similarities5. Embryological similarities

• Similar patterns of developmentSimilar patterns of development